A recent study by deCODE genetics, a subsidiary of Amgen, offers new insights into how body mass index (BMI) influences disease risk, suggesting that reducing BMI alone could lower the likelihood of developing certain diseases. Published in Nature Communications, this research analyzed genetic data from Iceland and the UK Biobank to explore whether the disease risks associated with obesity-related genetic variants are directly explained by BMI or by other factors.
The research team, led by Kári Stefánsson and Gudmundur Einarsson, used Mendelian Randomization techniques to assess whether BMI itself mediates disease risk or if other mechanisms are at play. They found that for certain conditions, such as fatty liver disease, glucose intolerance, and knee replacement, the genetic association with disease was fully explained by BMI. This suggests that these diseases are likely linked directly to a higher weight, meaning that lowering it could significantly reduce the risk.
For other conditions, such as type 2 diabetes, heart failure, and stroke, the link to disease risk was largely but not entirely explained by BMI, indicating that while it is a major factor, other mechanisms may also contribute. These findings were largely consistent across men and women, although some sex-specific differences emerged. For instance, the influence of BMI on myocardial infarction (heart attack) appeared to differ slightly between sexes, suggesting that factors like sex may modulate the relationship between BMI and disease risk for certain conditions.
“This study highlights the critical role BMI plays in the development of diseases commonly associated with obesity, suggesting that reducing BMI could have a positive impact on lowering disease risk,” the authors noted. The findings support the idea that managing weight could play an essential role in reducing the likelihood of these diseases and improving overall health outcomes.
The study also pointed out that certain residual risks may be due to factors beyond static BMI measurements, such as weight changes over time. This means that a person’s risk of disease may also be influenced by how their weight fluctuates throughout their life, rather than at a single point in time. The researchers noted that other aspects, such as lifestyle or genetic factors, might also explain some of the remaining risk associations.
The implications of these findings are significant for both preventive healthcare and public health strategies. Reducing BMI could potentially reduce the burden of diseases that are commonly comorbid with obesity, including heart failure, type 2 diabetes, and chronic kidney disease. While more research is needed to fully understand the relationship between BMI, genetic risk, and disease, this study adds to growing evidence that weight management is key in lowering disease risk across a wide range of health conditions.
Future research may delve further into the mechanisms that contribute to the residual risks observed in diseases not fully explained by BMI. Factors such as nonlinear relationships, lifestyle influences, or measurement variability could provide additional insights into how weight impacts health. For now, the study emphasizes that maintaining a healthy weight remains a potentially effective strategy for reducing disease risk, underscoring the role of weight management in public health and preventive medicine.
